The present invention relates to improvements in motor fuel dispensers, particularly of the master/satellite configuration to determine if leaks exist in connections between the master and satellite dispensers.
Master and satellite fuel dispenser configurations have been known for a number of years and are particularly prevalent for use in fueling large trucks which have gas tanks on both sides of the vehicle. These types of installations are common in truck stops. In the installation, the master and satellite are located on opposed sides of a driveway onto which the vehicle to be fueled is driven. The driver removes the hose from the master dispenser and actuates a switch on the master dispenser, commonly a handle lever that supports the nozzle when it is idle. He or she can then dispense gasoline through the nozzle into the tank located on the side of the truck adjacent the master dispenser. Then, by leaving the hose and nozzle of the master dispenser in the fuel tank, he can walk around to the other side of the truck and fuel the tank on that side of the truck from the satellite dispenser. Again, he or she lifts the nozzle from the handle on the satellite dispenser and fuels the tank from that side. Upon returning the satellite dispenser hose to the satellite dispenser handle and returning the master dispenser hose to the master dispenser handle, it is ascertained that the dispensing of fuel is complete and the total amount due can be computed.
Typically, the fuel to the master dispenser comes from an underground storage tank having a submerged turbine pump, which is activated when fuel is to be pumped. In a known configuration, the lifting of the pump handle on the master dispenser sends a signal to a processing unit in the master dispenser. The processing unit zeros out the last transaction information in the dispenser and actuates the submerged pump. A solenoid valve located downstream of the meter in the dispenser is held shut for a period of three to five seconds to permit pressure in the pipe from the submerged pump to the solenoid valve to build up. Known mechanical devices along the line from the underground tank to the master dispenser determine if a leak exists between the underground tank and the solenoid valve of the master dispenser. After the three to five second period for the leak test, the solenoid valve in the master dispenser is opened to permit dispensing of fuel from the master dispenser. The leak test performed conventionally only ascertains if a leak exists between the underground tank and the master dispenser.
However, should a leak exist between the meter of the master dispenser and the solenoid valve of the satellite dispenser, there is no way of ascertaining same until detected by a bubbling up of fuel through the roadway or some other undesirable means. Accordingly, there exists a need in the art for a method and apparatus for ascertaining the presence of a leak condition between a master and satellite dispenser.